The present invention relates to a transimpedance amplifier.
A transimpedance amplifier refers to an amplifier which converts a current signal provided as an input into a voltage signal using a transimpedance of the amplifier, amplifies the converted voltage signal, and outputs the amplified voltage signal. In order to obtain a high gain in a conventional transimpedance amplifier, a bandwidth of the amplifier should be sacrificed, and when wanting to implement an amplifier operating in a wide bandwidth, there is a trade off in which the gain should be sacrificed. Korean Patent Publication No. 2006-0064981 is a prior document of a conventional transimpedance amplifier.
In order to solve a problem of the conventional transimpedance amplifier described above, the present invention is directed to a transimpedance amplifier having a sufficient bandwidth and a high gain so as to operate at high speed.
Further, the present invention is directed to a transimpedance amplifier which is not sensitive to noise coming from a power source.
Moreover, the present invention is directed to a transimpedance amplifier maintaining a high gain without decreasing a bandwidth and having an excellent noise characteristic.
One aspect of the present invention provides a transimpedance amplifier including an inverter configured to have a feedback resistor and amplify a signal provided to an input side, and a common gate amplifier configured to be connected to the inverter in cascade and amplify an output of the inverter, wherein the signal provided to the input side is fed forward to a gate of the common gate amplifier through a gate resistor.
Another aspect of the present invention provides a transimpedance amplifier including an inverter configured to include a feedback resistor and amplify an input signal; and a common source amplifier configured to amplify the input signal, wherein the input signal is provided to a gate of the common source amplifier through a gate resistor, and an output signal of the inverter and an output signal of the common source amplifier are added in a common node.
According to an embodiment of the present invention, a high gain of the inverter and a wide operating bandwidth of a common gate amplifier may be obtained by having the inverter, the common gate amplifier, and a configuration in which the input signal is fed forward. Further, a low noise sensitivity characteristic may be obtained by the configuration described above.
According to an embodiment of the present invention, a transimpedance amplifier according to the embodiment may have advantages in which a high gain is obtained by adding signals amplified by the inverter and the common source amplifier, and also an excellent noise characteristic is obtained since noise included in the input signal is cancelled out in an output signal.